For many years, I lived in Westchester, took metro-north to grand central (30 minutes on an express train), then the 4/5/6 to work (10 minutes. 15 when things were slow).
I looked at this before leaving NYC and the problem is that once you add the time to get to the metro-north station, time to switch from metro north to subway, time from subway to office, and time waiting for trains, elevators, etc, you can easily have a 75-90 minute commute. And that's when things go right on two different transit systems, which seems far too rare these days.
Lately, Grand Central Station has become an overcrowded tourist nightmare where you have to do breathing exercises to stay calm getting from the station to the subway.
I cannot believe they put an Apple store in there. It should be a crime to choose profits over efficiency.